feat(ui themes): better place for theme list ctx, testing (#7163)

`AllThemes` is only used by `user/settings/appearance.tmpl`, not by all settings pages.

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/7163
Reviewed-by: Gusted <gusted@noreply.codeberg.org>
Co-authored-by: 0ko <0ko@noreply.codeberg.org>
Co-committed-by: 0ko <0ko@noreply.codeberg.org>

routers/web/user/setting/profile.go

@@ -329,6 +329,7 @@ func Repos(ctx *context.Context) {
 func Appearance(ctx *context.Context) {
 	ctx.Data["Title"] = ctx.Tr("settings.appearance")
 	ctx.Data["PageIsSettingsAppearance"] = true
+	ctx.Data["AllThemes"] = setting.UI.Themes
 
 	var hiddenCommentTypes *big.Int
 	val, err := user_model.GetUserSetting(ctx, ctx.Doer.ID, user_model.SettingsKeyHiddenCommentTypes)

routers/web/web.go

@@ -640,7 +640,7 @@ func registerRoutes(m *web.Route) {
 			m.Post("/unblock", user_setting.UnblockUser)
 		})
 		m.Get("/storage_overview", user_setting.StorageOverview)
-	}, reqSignIn, ctxDataSet("PageIsUserSettings", true, "AllThemes", setting.UI.Themes, "EnablePackages", setting.Packages.Enabled, "EnableQuota", setting.Quota.Enabled))
+	}, reqSignIn, ctxDataSet("PageIsUserSettings", true, "EnablePackages", setting.Packages.Enabled, "EnableQuota", setting.Quota.Enabled))
 
 	m.Group("/user", func() {
 		m.Get("/activate", auth.Activate)

tests/integration/appearance_settings_test.go

@@ -0,0 +1,48 @@
+// Copyright 2025 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package integration
+
+import (
+	"net/http"
+	"testing"
+
+	"code.gitea.io/gitea/tests"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestThemeChange(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+	user := loginUser(t, "user2")
+
+	testSelectedTheme(t, user, "forgejo-auto")
+
+	testChangeTheme(t, user, "forgejo-dark")
+	testSelectedTheme(t, user, "forgejo-dark")
+}
+
+// testSelectedTheme checks that the expected theme is used in html[data-theme]
+// and is default on appearance page
+func testSelectedTheme(t *testing.T, session *TestSession, expectedTheme string) {
+	t.Helper()
+	response := session.MakeRequest(t, NewRequest(t, "GET", "/user/settings/appearance"), http.StatusOK)
+	page := NewHTMLParser(t, response.Body)
+
+	dataTheme, dataThemeExists := page.Find("html").Attr("data-theme")
+	assert.True(t, dataThemeExists)
+	assert.EqualValues(t, expectedTheme, dataTheme)
+
+	selectorTheme, selectorThemeExists := page.Find("form[action='/user/settings/appearance/theme'] input[name='theme']").Attr("value")
+	assert.True(t, selectorThemeExists)
+	assert.EqualValues(t, expectedTheme, selectorTheme)
+}
+
+// testSelectedTheme changes user's theme
+func testChangeTheme(t *testing.T, session *TestSession, newTheme string) {
+	t.Helper()
+	session.MakeRequest(t, NewRequestWithValues(t, "POST", "/user/settings/appearance/theme", map[string]string{
+		"_csrf": GetCSRF(t, session, "/user/settings/appearance"),
+		"theme": newTheme,
+	}), http.StatusSeeOther)
+}